When the boiler first comes on from cold as it approaches 60c when heating it starts to make a rustling noise which disappears when it starts to level off and modulate around 68c. It is set at 68c and cuts out at around 70-71c. I have a magna clean above and am not sure if the rustling is coming from that? After it cuts out and cools it then comes back on but makes no rustling sound at all as it gradually heats again towards 68-70c. any ideas please? All I know is that this rustling has gradually got worse over time but doesn't appear to be effecting the boiler in any other way. I would of thought if it was Kettling t would be doing it all the time and not going away completely as it begins to modulate?? Thanks in advance.
